Note 2 - Investments - Components of EAM's Investment Management Operations (Details) - USD ($) $ in Thousands		3 Months Ended
		Jul. 31, 2022	Jul. 31, 2021
Revenues		$ 9,944	$ 10,166
Value Line’s non-voting revenues interest		2,782	4,149
EAM's net income		4,458	5,897
EAM Trust [Member]
Other income		8	72
Investment management fee waivers and reimbursements		(18)	107
12b-1 fee waivers		28	171
Value Line’s non-voting revenues interest		2,782	4,149
EAM's net income	[1]	466	1,312
EAM Trust [Member] | Investment Advice [Member]
Revenues		5,190	7,757
EAM Trust [Member] | Distribution and Shareholder Service [Member]
Revenues		$ 1,559	$ 2,454

[1] Represents EAM's net income, after giving effect to Value Line's non-voting revenues interest, but before distributions to voting profits interest holders and to the Company in respect of its 50% non-voting profits interest.